Fòram na Gàidhlig

I've got a question about terminology regarding other parts of Scotland from the POV of the Gàidhealtachd. Does the term 'Lowlander' (or its Gaelic equivalent) only get applied to people from the Lowlands, or could it also be applied to people from Orkney and Shetland as well? In my understanding the term generally applies to the eastern half of Scotland but I don't know whether the Northern Isles could be included under that label.

I ask because I'm looking at a song written by a fishing girl who got pregnant when she was at the herring gutting in Stronsay, and (singing in English) she warns other girls to never trust a Lowlander. I'm trying to figure out whether it's implied that the man was from the Lowlands but up in Stronsay just for the fishing, or whether the term 'Lowlander' could also mean he was actually from Orkney.

I'm also curious in general about where the Gaels consider the non-Gaelic-speaking Northern Isles to fall in the Highland/Lowland divide.

This is actually a pretty complicated subject. Highlands/Lowlands doesn't mean the same as Gàidhealtachd/Galltachd, since any Gaelic speaking community would be a Gàidhealtachd, but matter where it is. And of course, there are a lot of Gaels who didn't lean the language from their parents, so you can't simply say anybody who doesn't speak Gaelic is a Gall... Traditionally, I would say anybody who isn't part of a Gaelic community would have been considered a Gall.